Low-cost Battery Charger

The MAX8730 highly integrated, multichemistry, battery-
charger control IC simplifies construction of accurate
and efficient chargers. The MAX8730 operates at high
switching frequency to minimize external component
size and cost. The MAX8730 uses Analog inputs to con-
trol charge current and voltage, and CAN be pro-
grammed by a Microcontroller or hardwired.
The MAX8730 reduces charge current to give priority to
the system load, effectively limiting the adapter current
and reducing the adapter current requirements.
The MAX8730 provides a digital output that indicates
the presence of an AC adapter, and an Analog output
that monitors the current drawn from the AC adapter.
Based on the presence and absence of the AC
adapter, the MAX8730 automatically selects the appro-
priate source for supplying power to the system by con-
trolling two external switches. Under system control, the
MAX8730 allows the battery to undergo a relearning
cycle in which the battery is completely discharged
through the system load and then recharged.
An Analog output indicates adapter current or battery-
discharge current. The MAX8730 provides a low-quies-
cent-current linear Regulator which may be used when
the adapter is absent, or disabled for reduced current
consumption
The MAX8730 is available in a small, 5mm x 5mm, 28-
pin, thin (0.8mm) QFN package. An evaluation kit is
available to reduce design time. The MAX8730 is
available in a lead-free package. By Maxim Integrated Products